The [4+1] cycloaddition reaction of bifunctional amino reagents has been achieved with in situ formed aza‐ortho‐quinonemethides. Specifically, N‐(tosyloxy)carbamates were used as an N1 synthon and bifunctional amino reagents for this transformation, which provides a metal‐free, catalyst‐free, and oxidant‐free strategy to form nitrogen‐nitrogen bonds.
In this work we investigated, for the first time, the reactivity of sulfinimidate esters as an electrophilic sulfinimidoyl motif source. The reaction of such sulfinimidate esters with Grignardreagents enables the preparation of protected sulfilimines in high yields and with a remarkable structural variability. Moreover, the transformation can be performed in CPME (cyclopentyl methyl ether) as a green
Rh(II)-Catalyzed Nitrene-Transfer [5 + 1] Cycloadditions of Aryl-Substituted Vinylcyclopropanes
作者:Logan A. Combee、Shea L. Johnson、Julie E. Laudenschlager、Michael K. Hilinski
DOI:10.1021/acs.orglett.9b00594
日期:2019.4.5
Formal [5 + 1] cycloadditions between aryl-substituted vinylcyclopropanes and nitrenoid precursors are reported. The method, which employs Rh2(esp)2 as a catalyst, leads to the highly regioselective formation of substituted tetrahydropyridines. Preliminary mechanistic studies support a stepwise, polar mechanism enabled by the previously observed Lewis acidity of Rh-nitrenoids. Overall, this work expands
highly enantioselective one‐pot cascade sequence based on the combination of asymmetric amine and N‐heterocyclic carbene catalysis (AHCC) is also disclosed. This one‐pot three‐component co‐catalytic transformation between α,β‐unsaturated aldehydes, hydroxylamine derivatives, and alcohols gives the corresponding N‐tert‐butoxycarbonyl and N‐carbobenzyloxy‐protected β‐amino acid esters with ee values ranging
Solid-phase synthesis of peptides containing bulky dehydroamino acids
作者:Jintao Jiang、Shi Luo、Steven L. Castle
DOI:10.1016/j.tetlet.2014.12.097
日期:2015.6
A method of incorporating bulky α,β-dehydroamino acids such as dehydrovaline and dehydroethylnorvaline into peptides via solid-phasepeptidesynthesis is reported. The key step involves ring opening of an azlactone (i.e., oxazolone) containing the dehydroamino acid by the amino group of a resin-bound peptide. The use of Alloc-protected azlactones was key to the success of the process.